This Phase II proposal describes the development of bioreactive devices for use in commercially available MALDI-TOF mass spectrometers. Bioreactive devices are chemically or enzymatically derivatized mass spectrometer targets capable of modifying or purifying biomolecules prior to MALDI-TOF analysis. Described are Specific Aims of: 1) Perfecting target geometries to support highly reproducible mass mapping using targets derivatized with common proteases (e.g., trypsin, pepsin and a- chymotrypsin), 2), The development of new bioreactive targets for serial modification of proteins, and for use in sample clean-up (i.e, ion exchange targets), 3) The development of General Enzyme Immobilization kits that allow end users to immobilize proprietary enzymes in-house, and, 4) The use of bioreactive targets in combination with high-performance MALDI- TOF instrumentation for protein identification and characterization. The development of bioreactive targets is significant to health-related research by expediting the routine mass spectrometric characterization of biomolecules. Therefore, the long-term objective of the Phase II research is to supply bioreactive targets to biotech industries for use in basic research and high-throughput applications involving the sensitive and accurate mass spectrometric characterization of biomolecules. PROPOSED COMMERCIAL APPLICATIONS: The commercial potential of the bioreactive targets stems from a growing need for routine methods and devices capable of the high-performance analysis of biomolecules. The devices are meant to augment the (already) high-performance capabilities of MALDI-TOF mass spectrometry by expediting analytical sample preparations, such as enzvmatic digestion, without introducing artifacts into the analysis. The bioreactive targets represent a useful consumable product to be used with existing MALDI- TOF instrumentation and therefore represent a significant commercial product for use in the characterization of biomolecules.